Solution:CES production function covers large class of production functions the CES production function is based on large parameters. Thus the CES function has wider scope and applicability hence, the A is correct.
In the CES production function, B is the factor substitution parameter whose value ranges between 1 and ∞.
The elasticity of factor subsitution (Es) = (1/1+B) which is assumed to be constant.
It is dueto the constancy of elasticity of substitution that CES production takes the form of different types of production function.